These studies will examine the effects of various growth-promoting factors on cellular proliferation, differentiation and regeneration of rat pancreas (islet and acinar cells) in monolayer and organ culture. Efforts will be directed toward the development of relatively pure preparations of islet cells, as determined by linear scanning (quantitative morphological analysis) and biochemical techniques. These cells will then be transplanted to alloxan diabetic recipients in an effort to reverse the diabetes. Information gained in the foregoing studies will permit subsequent attempts at in vitro modification of donor tissue antigenicity prior to transplantation; highly inbred and non-inbred rats will be used as recipients.